in need for info

we are making our own privet server we got the scrips finally but
the only issue we are experiencing is the ip. maybe someone here on elitepvpers can help.
1-as server, do I have to give the server my internal IP or my external IP
thats basically what I want to know
but could be cause I'm behind a router.

please someone if you can please give me a hand here.
we fixed allot of the problems but for some reason we still can not access the server. we don't know if its the ip or what but it shows as if its accessing it even shows the attempt to access the server but we can not actually log on.